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arXiv · 2507.02040

Many-Body Simulations of the Fast Flavor Instability

Zoha Laraib·Sherwood Richers
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Abstract

The neutrino fast flavor instability dominates the evolution of neutrino flavor within the engines of core-collapse supernovae and neutron star mergers. However, theoretical models of neutrino flavor change that include many-body quantum correlations can differ starkly from similar mean-field calculations. We demonstrate for the first time that the inhomogeneous fast flavor instability is disrupted by many-body correlations using a novel tensor network framework that allows a continuous transition between mean-field and many-body results by tuning the singular value decomposition cutoff value. Generalizing the forward-scattering Hamiltonian to spatially varying conditions, we demonstrate that the timescale of flavor transformation scales logarithmically with system size, suggesting that many-body effects could occur before mean-field instabilities are able to saturate. Our results have significant implications for astrophysical explosion dynamics, nucleosynthesis, and observable neutrino signatures.

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Zoha Laraib, Sherwood Richers. 2025-07-02. Many-Body Simulations of the Fast Flavor Instability. https://doi.org/10.1103/d6w8-7j9s

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